Green tea caffeine: With everybody thinking green to preserve the planet, the next time you have a choice of white, green, or black, you might want to choose green—tea that is—to help preserve your heart.
There are thousands of varieties of teas available, each with a different taste, different health benefits, and varying levels of caffeine. While these differences are decided by growing region, when they were harvested, and processing method—all teas come from a plant called Camellia sinensis.
Green tea is currently the #1 choice due to its high level of antioxidants, which appear to help detoxify and fight cancer, help lower blood pressure, fight gingivitis and cavities, and help regulate blood sugar levels. Green teas are often mixed with fruits or scented with flowers and have only 5 to 10 percent the caffeine of coffee.
In a new study which appeared in the latest issue of European Journal of Cardiovascular Prevention and Rehabilitation, Dr. Nikolaos Alexopoulos and colleagues at the 1st Cardiology Department, Athens Medical School in Greece, found that the consumption of green tea rapidly improved the function of the endothelial lining (a thin layer of cells that line the interior surface of blood vessels) in the circulatory system. Endothelial dysfunction is a key event in the progression of atherosclerosis; a common arterial disease in which raised areas of degeneration and cholesterol deposits form on the inner surfaces of the arteries, obstructing blood flow.
In the random trial, ultrasound showed a greater dilation (3.9 percent) of the heart arteries in just 30 minutes for those given green tea over those given diluted caffeine or hot water. Researchers believe that green tea helps the cells in the lining of the blood vessels secrete the substance that is needed to relax the vessels and allow better blood flow. It's the flavonoids, (compounds found in fruits, vegetables, and certain beverages that have diverse beneficial biochemical and antioxidant effects) in the tea that work as antioxidants to help prevent inflammation in body tissue and keep the vessels pliable. "We found very promptly [that] after drinking green tea, there was a protective effect on the endothelium," said Dr. Charalambos Vlachopoulos, a cardiologist and one of the authors of the study.
It only took 6 grams of green tea, the equivalent of 3-4 cups, to cause arterial dilation and amazingly the beneficial effects seem to be cumulative and long-lasting. After two weeks of daily consumption of the beverage, the arteries of the green tea drinkers were measured and researchers found that their blood vessels were more dilated then they were when the study began. "It's something that needs to be investigated, but we think that if someone takes green tea for one or two months, the beneficial effect will be even greater," says Vlachopoulos.
Although this and previous studies show proof of theory, more research needs to be done before green tea can be labeled as a medical marvel. Dr. Robert Eckel, a professor at the University of Colorado, Denver, and past president of the American Heart Association, says "Green tea consumption may have beneficial effects on the arteries, but we should stop short of translating that into a recommendation that everybody should be drinking green tea because it's been proven to reduce heart attacks and stroke." To date green tea has not yet been included in the American Heart Association's dietary recommendations.
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